A sheet metal blank and a bent sheet metal component are disclosed, for example, in DE 10 2009 004 798 A1.
For the laser-welding of cases, hoods or other sheet metal constructions, the components are intended to be constructed in such a manner that the gap tolerance is complied with for the subsequent joining process. For a good welding result with adequate operational reliability, the triangular edges of the sheet metal construction may generally have a gap of a maximum of from 0.1 to 0.2 mm. In addition, the sheet metal members are intended to be constructed so as to overlap by a specific amount. In particular in the region of visible seams, an overlap of at least approximately 70% of the sheet metal thickness is recommended. Accordingly, the component preparation must provide a configuration of the corner which is intended to be taken into account between two bending members of the sheet metal blank forming the base.
Generally in the case of free bending without any additional requirements with respect to subsequent operating steps, at the intersection of the bending lines, for example, a ¾-circular recess is formed by punching having the diameter d. In this instance, the diameter is selected in accordance with the sheet metal thickness t.
From DE 10 2009 004 798 A1, it is already known to provide in the inner corner of the sheet metal blank located between two bending members a wedge-like recess (“free notch”, “corner notch”) which during the bending operation prevents squeezing and an associated swelling of the bending portion in this region. With this wedge-like recess, the gap width provided between the two bent sheet metal members can be reduced to a small gap dimension, as required for laser-welding of the two sheet metal members or with visible edges with a high level of requirements. However, owing to the narrow geometry thereof, the wedge-like recess can be produced only by laser-cutting. With thin metal sheets and a high number of items, however, punched blanks are more economical than laser blanks so that boxes having a thin wall thickness are currently welded together from a plurality of individual punched components.